Detailed Description
A foot-and-mouth disease antigen protective agent is composed of the following substances in percentage by mass and volume: 5 to 20 percent of carbohydrate reducing agent, 0.08 to 1.1 per mill of protein disulfide bond reducing agent, 1.5 to 4.5 percent of amino acid cosolvent and 0.5 to 3 percent of protein protective agent;
the sugar reducing agent comprises one or more of xylitol, lactose and fructose;
the protein disulfide bond reducing agent comprises DTT and/or TCEP.
DTT is Dithiothreitol, British name DL-Dithiothreitol, molecular weight 154.25. In some embodiments, the mass volume percentage of the DTT in the protective agent is 0.03% to 0.38%.
TCEP is Tris (2-carboxyethyl) phosphine, known in England as Tris (2-carboxyethyl) phosphine, molecular weight 286.7. In some embodiments, the TCEP is present in the protectant in an amount from 0.05 to 0.72% by volume.
The total nitrogen content needs to be measured in the vaccine quality detection for evaluating the purity of the antigen. Such as higher total nitrogen for the protective agent, or interference of the agent with the total nitrogen determination, will likely affect the objective assessment of vaccine quality. The components of the protective agent do not interfere with the determination result of total nitrogen, and do not influence the evaluation of the purity of the vaccine, the national standard and the GMP standard.
The foot-and-mouth disease antigen protective agent provided by the invention is reasonable in design and is very suitable for long-acting protection of the foot-and-mouth disease antigen.
The sugar reducing agent is preferably a polyhydroxy sugar, and is more preferably one or more of xylitol, lactose and fructose. The saccharide can be used as a reducing agent, has a co-dissolving effect, and can form a protective shell on the surface of a protein molecule to be protected to play a stabilizing role. The polyhydroxy sugar can form a hydration film on the surface of the virus capsid protein to be protected, and plays a role in stabilizing, and the protective capability of different sugars to antigens is different.
In some embodiments, the protective agent may further comprise the following substances in percentage by mass and volume: 9 to 15 percent of carbohydrate reducing agent, 0.16 to 0.5 per mill of protein disulfide bond reducing agent, 2 to 4 percent of amino acid cosolvent and 0.5 to 2 percent of protein protective agent. In some embodiments, the amino acid-based co-solvent comprises one or more of cysteine, glycine, arginine.
In some embodiments, the proteinaceous protective agent comprises albumin and/or serum protein.
Protein-based protectants can maintain the stability of the protein to be protected. The protein protective agents which can be selected without antigens are different, and corresponding experiments and detection are needed according to different antigens.
In some embodiments, the protective agent may further comprise the following substances in percentage by mass and volume: the composition comprises 18% of a carbohydrate reducing agent (6% of xylitol, 6% of lactose and 6% of fructose), 0.7% of a protein disulfide bond reducing agent (0.4% of DTT and 0.3% of TCEP), 4% of an amino acid cosolvent (1% of cysteine, 2% of glycine and 1% of arginine) and 1% of a protein protective agent (0.8% of albumin and 0.2% of serum protein); 5% of carbohydrate reducing agent (xylitol 2%, lactose 2%, fructose 1%), 1.1% of protein disulfide bond reducing agent (DTT 0.5% o, TCEP 0.6% o), 4.5% of amino acid cosolvent (cysteine 2%, glycine 1.5%, arginine 1%), 1.5% of protein protective agent (albumin 0.5%, serum protein 1%); 20% of carbohydrate reducing agent (12% of xylitol, 8% of lactose), 0.08% of protein disulfide bond reducing agent (0.03% of DTT, 0.05% of TCEP), 1.5% of amino acid cosolvent (0.5% of cysteine, 1.0% of glycine) and 2.5% of protein protective agent (1.2% of albumin and 1.3% of serum protein); 9% of a carbohydrate reducing agent (4% of xylitol and 5% of fructose), 0.16% of a protein disulfide bond reducing agent (0.16% of DTT), 2% of an amino acid cosolvent (1.2% of glycine and 0.8% of arginine) and 3% of a protein protective agent (3% of serum protein); 12% of carbohydrate reducing agent (lactose 8%, fructose 4%), 0.5% of protein disulfide bond reducing agent (TCEP 0.5%), 4% of amino acid cosolvent (cysteine 1.8%, arginine 2.2%), and 2% of protein protective agent (albumin 2%); 15% of carbohydrate reducing agent (xylitol 4%, lactose 5%, fructose 6%), 0.25% of protein disulfide bond reducing agent (DTT 0.12% o, TCEP 0.13% o), 3% of amino acid cosolvent (cysteine 1%, glycine 1%, arginine 1%), 0.5% of protein protective agent (albumin 0.3%, serum protein 0.2%) and the like.
In some embodiments, the composition of the protectant further includes an inorganic equilibrium salt; preferably, the inorganic equilibrium salt comprises: 60 to 100mM HEPES, 70 to 100mM EDTA, 20 to 40mM KCl, 10 to 20mM MgCl2One or more of (a).
In some embodiments, the concentration of the HEPES may also be 70mM, 80mM, 90mM, 95mM, etc.; the concentration of EDTA may also be 75mM, 80mM, 90mM, 95mM, etc.; the concentration of KCl may be 25mM, 30mM, 35mM, etc.; MgCl2The concentration of (b) may be 12mM, 15mM, 18mM, etc.; the above ingredients resulted in substantially consistent results over their respective concentration ranges.
In some embodiments, the composition of the protective agent further comprises 0.5 to 1.0mM urea.
The urea can enhance the ionic strength and increase the charge number of the urea, thereby being beneficial to long-term storage. In some embodiments, the concentration of urea may also be 0.6mM, 0.8mM, 0.9mM, etc. (results are essentially consistent within this range).
In some embodiments, the pH of the protectant is 7.2 to 7.9.
In some embodiments, the pH may also be 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, etc. (results are essentially consistent within this range).
Another aspect of the present invention is to provide a composition containing a foot-and-mouth disease antigen, which includes the above-mentioned protective agent.
In some embodiments, the foot and mouth disease antigen comprises an inactivated antigen and/or an inactivated antigen.
In some embodiments, the concentration of the active ingredient of the foot-and-mouth disease antigen in the composition is 1 to 200. mu.g/mL.
Preferably, the foot-and-mouth disease antigen solution is replaced by using an ultrafiltration concentration tube, so that the antigen is stored in the protective agent and can be stored for at least 18 months at 4 ℃.
Another aspect of the present invention is to provide a method for preparing a vaccine for foot-and-mouth disease, which comprises mixing the above-mentioned antigen for foot-and-mouth disease with the above-mentioned protective agent, adjusting pH, and sterilizing.
In some embodiments, the vaccine further comprises an adjuvant, which is added during the mixing.
Preferably, the adjuvant comprises ISA 206 or ISA201VG oil adjuvant.
In some embodiments, the aftosa antigen protective agent can be applied to effective antigen preservation in hog cholera, blue ear, pseudorabies whole virus inactivated vaccine and subunit vaccine.
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
The chemical reagents involved in the present application are shown in table 1.
TABLE 1 chemical reagents used
| Manufacturer of the product | Purity of |
| HEPES | sigma | Analytical purity |
| KCl | sigma | Analytical purity |
| Reduced matter | sigma | Analytical purity |
| EDTA | sigma | Analytical purity |
| MgCl2 | sigma | Analytical purity |
| NaOH | Beijing chemical industry | Analytical purity |
Example 1
60mM HEPES, 100mM EDTA, 20mM KCl, 20mM MgCl2Preparing 10X mother liquor from 0.5mM urea, weighing 20g of carbohydrate reducing agent (9 g of xylitol and 11g of fructose), 0.008g of protein disulfide bond reducing agent (DTT 0.003g and TCEP 0.005g), 4.5g of amino acid cosolvent (cysteine 2g, glycine 1g and arginine 1.5g) and 0.5g of protein protective agent (albumin and/or serum protein), dissolving the components in water, fixing the volume to 100mL, adjusting the pH to 7.2, sterilizing and filtering by using a 0.22um filter membrane, and storing at 4 ℃.
Example 2
100mM HEPES, 70mM EDTA, 40mM KCl, 10mM MgCl2Preparing 10X mother liquor from 1.0mM urea, weighing 5g of carbohydrate reducing agent (lactose 2g and fructose 3g), 0.11g of protein disulfide bond reducing agent (TCEP 0.11g), 1.5g of amino acid cosolvent (cysteine 1g and glycine 0.5g) and 3g of protein protective agent (albumin 1g and serum protein 2g), adding water to dissolve the components, fixing the volume to 100mL, adjusting the pH to 7.3, sterilizing and filtering by using a 0.22um filter membrane, and storing at 4 ℃.
Example 3
80mM HEPES, 90mM EDTA, 30mM KCl, 15mM MgCl2Preparing 10X mother liquor from 0.7mM urea, weighing 10g of carbohydrate reducing agent (6 g of xylitol and 4g of lactose), 0.04g of protein disulfide bond reducing agent (DTT 0.04g), 2g of amino acid cosolvent (glycine 0.8g and arginine 1.2g) and 2g of protein protective agent (albumin 2g), adding water to dissolve the components, fixing the volume to 100mL, adjusting the pH value to 7.4, sterilizing and filtering by using a 0.22um filter membrane, and storing at 4 ℃.
Example 4
70mM HEPES, 80mM EDTA, 25mM KCl, 18mM MgCl2Preparing 10X mother liquor by 0.8mM urea, weighing 15g of carbohydrate reducing agent (6 g of xylitol, 4g of lactose and 5g of fructose), 0.02g of protein disulfide bond reducing agent (0.01 g of DTT and 0.01g of TCEP), 4g of amino acid cosolvent (2 g of cysteine and 2g of arginine) and 1g of protein protective agent (1 g of serum protein), adding water to dissolve the components, fixing the volume to 100mL, adjusting the pH to 7.9, sterilizing and filtering by using a 0.22um filter membrane, and storing at 4 ℃.
Example 5
75mM HEPES, 90mM EDTA, 32mM KCl, 13mM MgCl2Preparing 10X mother liquor by 0.6mM urea, weighing 18g of carbohydrate reducing agent (5 g of xylitol, 8g of lactose and 5g of fructose), 0.06g of protein disulfide bond reducing agent (0.03 g of DTT and 0.03g of TCEP), 3g of amino acid cosolvent (1 g of cysteine, 1g of glycine and 1g of arginine) and 1.5g of protein protective agent (0.7 g of albumin and 0.8g of serum protein), dissolving the components in water, fixing the volume to 100mL, adjusting the pH to 7.7, sterilizing by using a 0.22um filter membrane, filtering, and storing at 4 ℃.
Experimental example 1
The aging experiment at 37 ℃ proves that I.
Setting comparative examples, the comparative examples are set on the basis of example 5, specifically:
comparative example 1: replacing the reducing agent with sucrose of the same mass;
comparative example 2: the proteinaceous protective agent was replaced with peptone of the same mass.
The buffer system of the antigen solution was replaced with the protectant for the foreign plant, the protectant for this product (example 5) and the buffer system in the comparative example by using a GE 100kD ultrafiltration concentrator tube, aseptically filtered, and then subpackaged in an EP tube, aged at 37 ℃ and subjected to an aging test with theaftosa 146S antigen without the protectant as a control for 3 days, 7 days, 11 days and 14 days. The content of the foot-and-mouth disease virus 146S is determined by Waters liquid phase detection (see Table 2), and the protection rate is calculated according to the detection result (see Table 3).
TABLE 237 ℃ aging 146S measurement results
TABLE 337 ℃ comparison of aging protection
As can be seen from tables 2 and 3, the protective rate of the protective agent in the embodiment can reach 75.71% after the protective agent is placed at 37 ℃ for 14 days, and 146S of the antigen without the protective agent is only preserved by 5.23%, so that the protective agent has obvious effect and is obviously superior to other manufacturers. Moreover, it can be seen from the comparative example that the protective effect is remarkably reduced after the corresponding components are replaced by sucrose which is the saccharide reducing agent or peptone which is the protein protective agent.
And (5) ageing experiment verification at 37 ℃ is two.
As can be seen from the 146S liquid phase detection spectrum in FIG. 1, the protective rate of the product after aging at 37 ℃ for 14 days is 75.71%, while the protective rate of the control group without the protective agent is only 5.23% against theantigen 146S, and the 146S loss is large.
Experimental example 2
The accelerated aging test at 45 ℃ proves that I.
In order to further verify the protection effect, the invention improves the thermal cracking resistance temperature, and adopts an aging experiment of samples accelerated at 45 ℃, wherein the sampling time is 3h, 6h and 9 h. The concentration of 146S of the foot-and-mouth disease virus was measured (see Table 4), and the protective rate was calculated from the results of the measurement (see Table 5).
TABLE 445 ℃ accelerated ageing 146S measurement results
TABLE 545 ℃ accelerated aging protection Rate comparison
As can be seen from tables 4 and 5, the protective agent in the example has a protective rate of 56.44% after accelerated aging at 45 ℃ for 9h, and has a significant protective effect compared with the antigen without the protective agent and other protective agents. Compared with antigen without protective agent, the protective effect is obvious and is obviously better than that of other manufacturers. Moreover, it can be seen from the comparative example that the protective effect is remarkably reduced after the corresponding components are replaced by sucrose which is the saccharide reducing agent or peptone which is the protein protective agent.
And (5) verifying by an accelerated aging experiment at 45 ℃.
As can be seen from the 146S liquid phase detection spectrum in FIG. 2, after 9 hours of 45 ℃ accelerated aging test, the 146S residual content of the protective agent is equivalent to 56.4 percent of the original protective agent at most, and the highest protective agent of other manufacturers is only 16.9 percent.
Experimental example 3
The effect of the protective agent on the toxicity value.
To investigate the effect of protective agents on the titer of antigens, we performed antigens using the BHK21 cell lineThe virus titer of the TCID50 virus titer is 10-6、10-7、10-8In each titer, 8 wells were assayed in parallel, antigen without protective agent was set as a control, and three replicates were performed to verify the degree of effect.
TABLE 6 TCID50 test results
| TCID50 | Other manufacturers 1 | Protective agent for product | Original antigen |
| Parallel experiment 1 | 10-7.25/0.1ml | 10-7.43/0.1ml | 10-7.33/0.1ml |
| Parallel experiment 2 | 10-7.25/0.1ml | 10-7.33/0.1ml | 10-7.25/0.1ml |
| Parallel experiment 3 | 10-7.33/0.1ml | 10-7.49/0.1ml | 10-7.33/0.1ml |
As can be seen from Table 6, the control mean value was 10-7.300.1ml, the protective agent is 10-7.400.1ml, the toxicity of the protective agent is slightly higher but the difference is not obvious, and the protective agent has certain protective effect on the original toxicity.
Experimental example 4
Viral particle completeness detection.
After accelerated aging at 45 ℃ for 9h, the virus particles added with the protective agent and without the protective agent are observed by using an electron microscope. The results are shown in FIGS. 3 and 4. It can be seen that after the protective agent is added and aged for 9h at 45 ℃, the whole virus particles still exist in the visual field observed by an electron microscope, but the particles are completely cracked after the antigen without the protective agent is aged for 9h at 45 ℃. The aging resistance effect of the protective agent is proved to be remarkable.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.